Impacted valgus fractures are an important subgroup of complex proximal
humeral fractures that have a good prognosis for healing because of the intact
medial capsular blood supply to the humeral head. Less severe forms of these
fractures can be successfully treated
nonoperatively1 or
with use of minimally invasive internal fixation
techniques2.
However, when severe impaction of the humeral head and displacement of the
tuberosities occur, restoration of adequate shoulder function depends on
successful reduction and stabilization of these structures.
Although adequate reduction of the key fracture fragments can be achieved
with use of minimally invasive techniques, it has been our experience that
maintaining reduction is often difficult with percutaneous internal fixation
techniques. Secondary displacement of both the humeral head and the
tuberosities often occurs, perhaps because of instability caused by the
cancellous bone defect behind the reduced humeral head and by the inadequacy
of screw fixation alone. We developed a new open operative technique in an
attempt to address these problems. A stable fracture configuration following
reduction of the humeral head is achieved by filling the resultant defect with
bone substitute, and subsequent internal fixation is augmented by interosseous
suture repair of the tuberosities.
We believe that the procedure ideally should be performed within the first
week after the injury, although it is often feasible to reduce the fracture
fragments as late as two weeks after the injury; we recently performed the
surgery at this later stage for patients in whom the diagnosis had been
delayed. After the induction of general anesthesia, the patient is positioned
supine in the beach-chair position, with a shoulder operating table
"cut-away" to facilitate access for the image-intensifier from the
opposite side of the table. It is important to ensure secure fixation of all
anaesthetic tubing, which should be cleared from the path of the
image-intensifier to prevent inadvertent detachment during surgery. By
rotating the image-intensifier, both anteroposterior and
"modified"
axial3 views can be
obtained during surgery to assess the fracture reduction, to monitor the
insertion of bone substitute, and to visualize the position of the internal
fixation (Figs. 1-A, 1B,
1C, and
1-D). Routine antibiotic and
antithrombotic prophylaxis is used for all patients. The whole arm is prepared
and draped in order to allow free movement of the arm by the assistant during
surgery.
We use a deltoid-splitting approach through a shoulder-strap skin incision
because it provides better access to the humeral head and tuberosities than
does a standard deltopectoral approach
(Figs. 2-A and 2-B). The
modified skin incision is more cosmetically acceptable than the standard
longitudinal deltoid-splitting approach and is especially preferred by women
because the scar is easily concealed by the bra strap. A distally based
elliptical flap is developed (Fig.
3) to allow the deltoid to be split longitudinally over a
substantial length (Fig. 4).
The axillary nerve is in close proximity to the fractured tuberosities and the
displaced humeral head, and it is routinely identified and protected
throughout the procedure (Fig.
5). The path of the nerve as it runs transversely across the
deltoid split creates two soft-tissue windows. The window above the nerve
allows access to the humeral head and tuberosities for reduction and
stabilization, and the window below the nerve allows access to the proximal
part of the humeral shaft and creates a safe area for screw insertion if plate
fixation is required. A standard anterior acromioplasty is performed for all
patients to reduce the risk of later rotator cuff impingement.
After retraction of the deltoid, the split in the tuberosities is
identified to allow access to the humeral head. This split usually is readily
apparent because the humeral head is typically facing superiorly or
superolaterally with the tuberosities splayed on either side of it
(Figs. 6-A and 6-B). In most
patients, both tuberosities are fractured and substantially displaced,
although the displacement of the greater tuberosity is often more readily
apparent because of its larger size. A substantial rent in the rotator cuff,
propagating through the rotator interval, also is not uncommon and, if
present, is repaired later with nonabsorbable sutures. Next, three or four
nonabsorbable interosseous sutures are inserted through each tuberosity to
facilitate handling. The humeral head is elevated and reduced with a blunt
dissector under image-intensifier control (Figs.
7-A and
7-B). The humeral shaft tends
to displace medially below the humeral head, and we have found that the
insertion of a custom-made bolster into the axilla at this point helps to
lateralize and reduce the humeral shaft under the humeral head at the site of
the fracture and also helps to avoid excessive handling in this potentially
unsterile area (Fig. 8). Once
the head is adequately reduced, it is temporarily secured with threaded
Kirschner wires that are inserted through the proximal part of the humeral
shaft and into the head.
The metaphyseal cavity that is created behind the humeral head after it has
been reduced is irrigated to clear away blood and debris, and then the cavity
is filled with Norian Skeletal Repair System (SRS) bone substitute (Norian,
Cupertino, California). As with ordinary bone cement, the material is injected
in a semiliquid form, although the curing time is slower (fifteen minutes). A
specially designed cement gun with a narrow cannula is used to deliver the
cement to the deepest recesses of the cavity, after which it is gradually
withdrawn to fill the more superficial areas in a retrograde fashion. Careful
monitoring with an image-intensifier is required throughout the injection
process to ensure that there is no extravasation of cement into the soft
tissues. The greater and lesser tuberosities are then sutured together by
tying the interosseous stay sutures to create a closed cavity behind the
humeral head to contain the SRS during setting
(Fig. 9). We believe that
these interosseous sutures are critical to the stability of the reconstruction
and help to prevent early tuberosity pull-off.
INDICATIONS:
Patients with a severely impacted valgus fracture of the proximal part of
the humerus who are medically fit for anesthesia, who are less than
eighty-five years old, who are mentally alert and oriented (with a mini-mental
test score4 of >8
of 10), and who have a history of normal shoulder function prior to the injury
should be considered for surgery.
We believe that patients who have an impacted fracture in which the
inclination angle (the angle between the intramedullary axis and the
perpendicular to the articular surface margin) has been tilted into
=160° of valgus are suitable candidates for treatment with this
technique. Most of these patients also have substantially displaced tuberosity
fractures.
CONTRAINDICATIONS:
Medically frail, demented, and uncooperative patients and patients who are
more than eighty-five years old are treated nonoperatively in our unit,
irrespective of the apparent severity of their impacted valgus fracture as
seen on radiographs. Relative contraindications to surgery include rheumatoid
arthritis, prolonged type-I diabetes, immunocompromise, a history of heavy
smoking or alcoholism, and the presence of severe risk factors for
osteoporosis.
We believe that most fractures in which the inclination angle has been
tilted to <160° are best treated nonoperatively, although we consider
surgery for younger individuals (those who are sixty years old or less) if the
tuberosities are substantially displaced. The technique is inappropriate when
there is massive impaction (creating a volume of >20 mL to be filled)
behind the humeral head after it has been reduced. In these circumstances, we
use either a structural allograft (for uncontained defects) or morselized
allograft (for contained defects) to fill the large void behind the humeral
head. We believe that this technique is also inappropriate for fractures in
which the humeral head is either separated from the tuberosities and shaft or
dislocated from the glenoid cavity. Although we now treat many of these
fracture patterns with a humeral head-conserving procedure, the massive
comminution that is usually encountered means that the use of bone substitute
is not feasible and allograft is used instead.
PITFALLS:
Adequate patient selection is important because the rehabilitation program
that is used to regain shoulder function following surgery is prolonged and
often arduous. There is a substantial learning curve, particularly with regard
to arranging the table and the image-intensifier, patient positioning, and the
surgical approach and operative techniques used to gain adequate fracture
reduction and stabilization. We believe that the procedure is best performed
by an experienced trauma surgeon with an interest in shoulder surgery. It is
important to have stringent preoperative criteria for selecting fractures that
are suitable for the technique. As the bone substitute is injected in a
semi-liquid form, it is mandatory for it to be injected into a contained bone
defect. Fractures in which the medial soft-tissue hinge is disrupted or in
which the head has become detached from the shaft are unsuitable for this
technique because injection usually results in extrusion of the bone
substitute into the soft tissues.
AUTHOR UPDATE:
In general, we believe that many of these more complex fractures of the
proximal part of the humerus, which would have been deemed to be
unreconstructable and treated with hemiarthroplasty ten years ago, can now be
treated with a humeral head-conserving procedure as a result of the new
technologies that are now available. Since the time of publication of our
original article and as our experience has grown, we have introduced
modifications to the technique.
As described above, we now routinely identify and protect the axillary
nerve throughout the procedure. The greater safety that this manuever affords
during insertion of internal fixation devices has resulted in a trend toward
the use of plate fixation rather than more minimal individual screw fixation
to stabilize the reconstruction. We now use plate fixation in the majority of
our patients because we believe that it imparts greater mechanical stability
to the reconstruction.
As our confidence in the stability of our reconstructions has grown, we
have reduced the period of postoperative immobilization from six to four
weeks.
Younger patients (those who are less than sixty years old) may commence
active-assisted range-of-motion exercises immediately postoperatively.
Initially, we rested all shoulders in internal rotation (the so-called safe
position) postoperatively. We now place the shoulder in a position of neutral
rotation, neutral flexion, and neutral abduction, with the elbow flexed to
90°, with use of a custom-made splint
(Fig. 12). We believe that
this facilitates the early recovery of shoulder movement once the sling has
been removed.
The fracture reduction is then stabilized by internal fixation with
positional screws, without any attempt being made to compress the osteoporotic
metaphyseal bone. In patients who have a single greater tuberosity fragment,
stabilization can be achieved by fixing the greater tuberosity to the humeral
head and/or proximal humeral metaphysis with use of two, three, or four 3.5-mm
partially threaded cannulated screws. In patients who have substantial
comminution of the greater tuberosity (more than two separate fragments),
secure fixation with screws alone is not possible, and a contoured cloverleaf
buttress plate is used to maintain the reduction
(Figs. 10-A and 10-B). Care
must be taken to avoid any tension on the axillary nerve as the plate is
inserted underneath it. Similarly, the nerve must be carefully protected
during insertion of the two or three cortical screws into the lower end of the
plate, through the lower soft-tissue "window."
All hardware should be placed as low as possible in the tuberosities in
order to minimize the risk of later impingement. If a plate is used, it is
important to ensure that it is positioned correctly below the apex of the
greater tuberosity (as seen on the image-intensifier) in order to reduce the
risk of later impingement. The anterior leaf of the plate should be placed
just posterior to the bicipital groove. It is also essential to ensure that
none of the screws are inadvertently placed within the joint. Several
safeguards are available to avoid this problem. First, the drill is inserted
at low speed and can be felt to encounter resistance when it comes into
contact with the hard subchondral bone of the humeral head. Second, the depth
gauge is advanced similarly until the hard subchondral bone is felt. Third,
screw length is a compromise between avoiding the joint penetration that
results from the use of a screw that is too long and the poor fixation that
results from the use of a screw that is too short; however, most screws that
are inserted into the head should be between 40 and 50 mm in length, if placed
properly. Fourth, once all screws have been inserted, careful final screening
should be carried out with use of the image-intensifier, with the shoulder
positioned in full internal and external rotation on both the anteroposterior
view and the modified axial view (Figs.
11-A and 11-B).
After copious lavage of the wound with saline solution, a meticulous suture
repair of the deltoid is required, especially at the top end of the incision,
where the deltoid is detached from the acromion. Early redetachment of the
deltoid is a potentially disastrous complication of this approach. We use
multiple interrupted nonabsorbable sutures for the lower end of the repair,
and we use multiple transosseous sutures to repair the upper end of the
deltoid to the acromion. A layered closure of the subcutaneous tissues and
skin is then performed.
In all patients, the shoulder is immobilized in a sling for four to six
weeks after the operation. Pendulum exercises and elbow range-of-motion
exercises are commenced immediately, with active-assisted range-of-motion
exercises beginning at two weeks after the operation. Abduction of the
shoulder beyond 90° or external rotation beyond the neutral position are
prohibited during this period. Isometric rotator cuff exercises and graduated
active range-of-motion exercises, performed under the supervision of a
physiotherapist and supplemented with a home-exercise program, are commenced
after removal of the sling and then are continued for at least six months
after the operation.